The Irish are a lovely people - but when it comes to addresses they are certifiably mad.

One particular problem is posed by "terraces" - usually several houses built in such a way that each pair of neighbours shares one wall.

Quite often those terraces have their own street sign - inside a longer street.

One example:

In Killarney there's Rock Road, oriented roughly north/south.

Halfway up Rock Road, on the east side of the road only, there are two street signs for "Allman's Terrace" with a dozen houses between them, numbered from 1 to about 30, then the sequence of numbers for Rock Road continues.

Is there anything that can be done in OSM to enable Navigator to find these addresses?

Simply renaming that part of Rock Road to Allman's Terrace isn't a solution, as I've found even crazier combos - where the (asphalt of the) street itself has one name, the terrace on one side has a second name, the terrace on the other side has a third name - all with their own street signs.

Currently the addresses are not correct according OSM as they are for example addr:housenumber=13-16. This becomes a label instead of a number in OSM standards. I don't know whether MNF stumbles on this or simply reads it as housenumber "13-16" (but currently it is not reading it anyway, so maybe with street but you don't want that here).

Correctly tagged this would have the tag: addr:interpolation=13-16 instead of the housenumber tag.

In Poland, Russia, Japan, Germany, Africa are many examples for addresses without a street. I didn't know this existed as well for Ireland but it doesn't surprise me. Japan, Brazil and Russia also use blocks with housenumbers as address instead of street-housenumber.

MNF does handle the addresses correctly here (bit sloppy in positioning them) but I do not know which tags are used to index the addresses. The "Burgau OSM mapper" uses the addr:place=Burgau tag. It is how more mappers do it, but it is advised not to use the tag for this kind of "street less" addressing.

If Osmand encounters such an address without street it searches for the smallest surrounding admin boundary which encloses the address, which works nicely as well.

As both MNF and the map making are closed source I have no idea how MNF does it.

This particular address was collected but did not pass conversion process due to missing street name. I see there Gaelic "addr:street:ga" "Ardán Almán", but no matching "addr:street". Under which (street) name the houses should be found?

It is one of those streetless addresses. That's why I gave the example of Burgau (and the others) where MNF does pick up the right addresses without streetname, and why I asked which data approach the map creation process is using.

Well, Burgau is different (see for example https://www.openstreetmap.org/way/240355206)it has:addr:housenumber 5addr:place Burgauaddr:street Burgaui.e. at the moment you should be able to find it via street "Burgau". If there are similar examples in Germany, we should add it to group of Czech Republic, Slovakia and Poland where "TOWN HOUSE NUMBERS" are collected also from tag "addr:place". Is similar numbering also in other countries?

You are right about that streetname for Burgau. I completely missed that. That's actually a big NO in the OSM community. You should never map for applications not being able to interpret addresses the way they really are. This is really adding incorrect information to make sure your app can find that address.

In Poland there are many, many occurrences of addresses in small communities which really do not have a streetname because the 1-3 streets really have no name (so not simply missing data in OSM), but I don't know these examples. Maybe some of the Polish members in this forum can give good examples. I think @PrzemekSupakis Polish.

I don't have direct other examples, but for example in Russia you have addresses that are building names followed with housenumbers in that building, again: addresses without streetnames.

Additional question: I've added a few more "interpolation" tags; there are a number of places I know of (such as the southern end of Rock Road) where there are several (up to four) nameless terraces (at least there are no signs, and none of the inhabitants I asked knew anything about a terrace name), so that now the same numbers appear more than once for the same street name.Can this create a problem for MNF, and if so, how can this be resolved?

Well, to be honest it will almost surely fail (in MFN). The necessary conditions are:1) add tag "addr:place" where is the name of city/town/village where number should be found2) we have to add ireland_osm into list of countries to process "town numbers"

Note, that "block interpolation" will not work in MFN case, only when it is related to street (i.e. start/end coordinates). This may change in the future.